Dumper

ABSTRACT

A dumper particularly for parts containers of various sizes and comprising a cradle mounted for swinging movement from a loading position to an unloading position. Power means for swinging the cradle includes a pinion which engages a rack that is preferably in the form of a link chain. Limit switches are provided to stop and/or reverse the power means at each end of the swing of the cradle.

United States Patent 11 1 Rivers [4 1 May 20, 1975 DUMPER [76] Inventor: Charles F. Rivers, 15318 Warwick Rd., Detroit, Mich. 48-223 [22] Filed: Mar. 4, 1974 [2]] Appl. No.: 447,947

Primary ExaminerRobert J Spar Assistant Examiner- Lawrence J. Oresky Attorney, Agent, or Firm-Whittemore, Hulbert & Belknap 1 1 ABSTRACT A dumper particularly for parts containers of various sizes and comprising a cradle mounted for swinging movement from a loading position to an unloading position. Power means for swinging the cradle includes a pinion which engages a rack that is preferably in the form of a link chain. Limit switches are provided to stop and/or reverse the power means at each end of the swing of the cradle.

10 Claims, 6 Drawing Figures P/UENTED HAY 2 0 [875 SHEET 2 BF 3* FIG.2

DUMPER SUMMARY OF THE INVENTION In the dumper of this invention, the cradle drive is such that the cradle may be tipped up over-center as much as 180 during unloading. The cradle drive is of the rack and pinion type so that the cradle is under control at all times and driven under power in both directions. Preferably the drive for the cradle comprises one or more stationary chains, acting as racks, engaged by sprockets powered from a drive mounted on the back of the cradle. There is virtually no chain wear because there is no chain movement. Consequently, practically no maintenance is required. Dumpers of this general type which in the past have been operated by a lift mechanism of the cable pull type have relied on gravity for returning the cradle to the loading position. Cradles so powered could not be tipped over-center during unloading because of the obvious inability of the lifting cables to push the over-center cradle back to the loading position. Other types employing endless linear drive members attached to the cradle are more costly and also require more maintenance because of the added wear.

The dumper of this invention employs adjustable hold-down devices or clamps so that containers of various heights and widths can be handled without obstructing the area over the top of the container.

The dumper is designed to reduce if not entirely eliminate the spillage of parts, is simple in construction and relatively trouble free in operation.

IN THE DRAWINGS FIG. 1 is a side elevational view of a dumper embodying my invention, showing the cradle in loading position in solid lines and in unloading position in dot-dash lines.

FIG. 2 is a rear view of the dumper shown in FIG. 1, with parts broken away and in section.

FIG. 3 is a fragmentary view taken on the line 33 in FIG. 1.

FIG. 4 is a view taken on the line 44 in FIG. 1.

FIG. 5 is an enlarged fragmentary view with parts in elevation and parts in section of a portion of FIG. 1.

FIG. 6 is a wiring diagram.

Referring now more particularly to the drawings, the dumper, generally designated 10, comprises an upright frame 12 and a cradle 14.

The frame 12 may be of any suitable construction and in the present instance is composed of the laterally spaced front uprights l6 and 18 and the laterally spaced rear uprights 20 and 22. These uprights are connected together by top, bottom and intermediate cross frame members 23, 24 and 25. The parts of the frame are thus joined together to form a rigid supporting structure. The front and rear of the frame 12 is open between the top and bottom cross members to permit the cradle to be loaded and to swing from loading to unloading position.

The cradle 14 in the present instance is of generally rectangular form having a bottom plate 26, upright side plates 28 and 30 and an upright rear plate or wall 32. The side and rear plates are connected along their adjacent edges to close the cradle on three sides. The cradle is open both at the front and at the top. The rear plate or wall 32 has an upwardly and forwardly inclined portion 33 at the top providing a discharge lip 34 at its upper edge over which the parts are discharged during unloading. The side plates or walls 28, 30 will be seen to rise to the upper edge or lip 34 of the rear wall and to enclose the sides of rear wall portion 33 to prevent spillage of the parts during operation of the dumper.

The cradle 14 is pivoted to the supporting frame 12 by a pivot shaft 36 for swinging movement from the lower position shown in solid lines in FIG. 1 in which the bottom plate 26 of the cradle is substantially horizontal to the unloading position shown in dot-dash lines in which the cradle has been turned through an angle approaching and in which unloading position parts are discharged over the rear lip 34 of the cradle into any receptacle provided for the purpose. When moved from loading to unloading position, the cradle moves over-center, that is its center of gravity moves from the front side of pivot shaft 36 to the rear side thereof. The pivot shaft 36 extends horizontally between and is terminally secured to the rear uprights 20, 22. The upper rear edge portions of the spaced upright channels 37 along the rear wall 32 of the cradle are pivotally mounted on the shaft 36 permitting swinging movement of the cradle from the loading to the unloading positions of FIG. 1.

A power driveunit 38 is provided to swing the cradle between loading and unloading positions. The power drive unit 38 comprises an electric motor M mounted on a support or bracket 42 rigidly secured to and projecting from the rear wall 32 of the cradle. The motor drives the cradle through a rack and pinion transmission 44.

The rack and pinion transmission 44 includes one or more elongated flexible, inextensible link chains 46, which act as racks. In the present instance, two such chains are employed, one along each side of the upright frame. An arcuate channel 48 is secured to the inner sides of the front and rear uprights 16, 20 and a second arcuate channel 48 is secured to the inner sides of the front and rear uprights l8 and 22. These channels extend through a substantial arc, in the present instance something less than 180. The arcs of the channels are centered on shaft 36. The channels are formed so that their side flanges extend radially outwardly from the channel base. A chain 46 is disposed in each channel 48, extending lengthwise thereof throughout more than the full length of the channel and terminally connected to the supporting frame as shown in the drawings. The upper end of each chain is connected to a frame member where indicated at 50, and the lower end of each chain is connected to a frame member indicated at 52. As seen best in FIG. 1, the lower end of the chain is connected to a block 53 carried on the end of a screw 55 threaded in frame member 52. Rotation of screw 55 will tighten or loosen the chain. The connection between screw 55 and block 53 is a swivel connection so that rotation of the screw will not twist the chain. The chains thus extend along the arcs defined by the channels, and are held reasonably taut by the pinions of the rack and pinion transmission. as will become more apparent as this description proceeds.

The rack and pinion transmission also includes two drive sprockets 54, one for each chain. The drive sprockets are mounted on the ends of a horizontal transverse shaft 56 disposed to the rear of the cradle beneath motor M. This shaft is journaled for rotation in cradle extensions 58 and is power driven from the motor M by means of a drive chain 60 passing over sprockets 62 and 64 on the motor and on shaft 56 respectively. The drive sprockets 54 are in driving engagement with chains 46. The drive sprockets are positioned to travel a path slightly radially outwardly of the base of the channels 48. As clearly seen in FIGS. 1 and the drive sprockets 54 engage the chains 46 on the inner sides of the arcs defined by the chains.

The transmission also includes the idler sprockets 66 and 68. The idler sprockets 66 are mounted on the end of a horizontal shaft 67 journaled for free rotation in the cradle extensions 58 just in front of the drive shaft 56. These idler sprockets are disposed immediately ahead of the drive sprockets 54 and engage the chains on the outer side of the arcs. The idler sprockets 68 are mounted on the ends of a horizontal transverse shaft 72. Idler shaft 72 is mounted for free rotation in cradle extensions 58 just to the rear of drive shaft 56. The idler sprockets 68 engage the chains just behind the drive sprocket 54 on the outer sides of the chain arcs.

It will be apparent that when the electric motor M is driven in one direction to power rotate the drive sprockets 54, the cradle may be raised from the loading position shown in solid lines in FIG. 1 to the unloading position shown in dot-dash lines. The cradle may be power driven in the opposite direction back to its loading position by reversing the electric motor M. Limit switches may be provided for stopping and/or reversing the electric motor. A limit switch LS1 mounted on the upper portion of the frame 12 is adapted to be engaged by a cradle part 76 when the cradle arrives at its upper unloading position to either stop the electric motor or reverse it. A second limit switch LS2 is mounted on the lower portion of the frame 12 in position to be engaged by a cradle part 76 when the cradle arrives at its lower loading position to either stop or reverse the electric motor.

FIG. 6 illustrates suitable circuitry for reversing the motor at the upper and lower limits of cradle movement. The control circuit 100 has a solenoid A in the line 102. The normally open limit switch LS1 in line 102 is inside a bypass circuit 104 in which is located a normally open contact A0 of the solenoid A. The solenoid A also has a normally closed contact AC in line 105 of the circuit 106 of motor M. The control circuit has a solenoid B in the line 108. The normally open limit switch LS2 in line 108 is within the by-pass circuit 110 in which is located the normally open contact B0 of the solenoid B. Solenoid B also has a normally closed contact BC in line 107 of the motor circuit. It will be noted that limit switch LS1 has a second contact 2LS1 in line 108 and LS2 has a second contact 2LS2 in line 102.

FIG. 6 illustrates the condition of the control circuit when the cradle is moving up to unloading position and is between limits. In this condition, the solenoid B is energized through the by-pass circuit B0 and its normally closed contact BC is open to ground one side of the motor circuit for motor operation in one direction. At the upper limit, limit switch LS1 is momentarily closed to energize solenoid A and open its normally closed contact AC to ground the other side of the motor circuit. At the same time, the switch 2LS1 opens to deenergize solenoid B and close its normally closed contact BC to reverse the current to the motor. The motor reversal will cause the cradle to move away from and open limit switch LS1, but solenoid A continues to be energized through its contact A0 in the by-pass cir cuit I04. At the unloading position when the cradle closes limit switch LS2, solenoid B is again energized and solenoid A is de-energized to reverse the motor a second time. Accordingly, the cradle will continue to move back and forth between loading and unloading positions.

It may be desired to have the motor simply shut off when the cradle reaches either limit. This is very easily accomplished in the motor circuit by a normally closed limit switch in one side of the motor circuit opened by the cradle at one limit and a second normally closed limit switch in the other side of the motor circuit opened by the cradle at the other limit. Manual start switches by-passing each of the limit switches can then be provided to restart the motor.

The cradle is intended for use with a suitable container adapted to hold the parts to be handled by the dumper. The container may be any suitable skid box, wire crate or the like. In the present instance, the skid box indicated at 82 is a simple rectangular container having a bottom and four upright sides of a width and length capable of fitting in the cradle and being supported upon the bottom wall of the cradle against its rear plate. As noted above, the front of the cradle is open to allow the skid box to be placed in the cradle and removed.

The skid box must be held down in the cradle to prevent it from dropping out during unloading. For this purpose, the angularly shaped hold-down dogs or stops 84 are provided with means for vertically adjustably mounting the stops on the cradle to accommodate skid boxes of differing heights. As seen, each side plate 28, 30 of the cradle has a pair of vertical slots 86 of sufficient width to receive the dogs 84. Pairs of vertical ribs 88 are secured to the outer sides of the cradle along the opposite sides of each slot. Each pair of ribs 88 is formed with a series of transversely aligned holes 90 which are spaced apart vertically the same distance as the spacing between the holes 92 in one leg of each stop. Hence a stop may be secured in vertically adjusted position in a slot by a cotter pin or the like 94 extended through the aligned holes 90 and 92 in one leg of the stop and in the ribs 88, with the other leg of the stop projecting into the cradle over the rim of the box to hold it down.

In use, and with the cradle 14 in the solid line position of FIG. I, the skid box 82 loaded with parts is placed inside the cradle against the rear wall of the latter. The hold-down stops 84 are adjusted, depending upon the height of the skid box, to extend over the rim of the box and hold it down during dumping. Obviously the skid box could be of a different length and still fit in the cradle. Even differing widths may be accommodated because of the length of the horizontal legs of the dogs. If desired, the stops 84 may be adjusted a slight distance above the rim of the skid box so that when the cradle is turned over to the dot-dash line position in FIG. 1, the skid box will drop against the stops and thereby jar all of the parts loose for discharge.

The motor M is started to rotate the cradle counterclockwise in FIG. 1 to the unloading position shown in dot-dash lines At that position, the cradle operates the limit switch LS1 which as previously stated may be of the type which either opens the circuit to motor M to stop it or reverses the circuit to reverse the motor and drive the cradle back to the loading position. The limit switch LS2 is contacted by the cradle in the loading position which as before indicated may be either of the type to open the circuit to the motor and stop it or to reverse the circuit and hence reverse the motor.

When the cradle is in loading position, the skid box may be re-loaded with parts or replaced by another loaded skid box.

The rack and pinion drive provided by the chains 46 and sprockets 54, 66 and 68 provides a positive drive for the cradle in both directions of cradle movement. Hence the cradle may move over-center during unloading even in excess of 180 if desired and may be returned from the unloading position by a mere reversal of the drive.

What I claim as my invention is:

l. A dumper comprising a supporting frame, a cradle, pivot means mounting said cradle on said frame for swinging movement from a loading position to an unloading position, and means for swinging said cradle from said loading position to said unloading position comprising a rack extending in an arc centered on the axis of swinging movement of said cradle, a pinion carried by said cradle in engagement with said rack, and power means on said cradle for rotating said pinion.

2. The dumper defined in claim 1, wherein said rack is a link chain, and said pinion is a sprocket.

3. The dumper defined in claim 2, including idler sprockets carried by said cradle on opposite sides of said first-mentioned sprocket, said first-mentioned sprocket engaging one side of said chain and said idler sprockets engaging the opposite side thereof.

4. The dumper defined in claim 2, wherein said chain is flexible and inextensible, and including an arcuate guide for holding said chain in an arc as aforesaid.

5. The dumper defined in claim 1, wherein said cradle is adapted to hold a parts container such as a skid box, hold-down means for holding the container down in said cradle comprising a stop engageable with the container, and means for adjiustably mounting said stop on said cradle to hold down containers of various sizes.

6. The dumper defined in claim 2, including idler sprockets carried by said cradle on opposite sides of said first-mentioned sprocket, said first-mentioned sprocket engaging one side of said chain and said idler sprockets engaging the opposite side thereof, said chain being flexible and inextensib'le, and an arcuate channelshaped guide for holding said chain in said are as aforesaid.

7. The dumper defined in claim 6, including limit switches engageable by said cradle to stop or reverse said motor when said cradle reaches loading and unloading positions respectively.

8. The dumper defined in claim 7, wherein said cradle is adapted to hold a parts container such as a skid box, hold-down means for holding the container down in said cradle comprising stops engageable with the rim of the container, and means for mounting said stops on said container in adjusted position.

9. The dumper defined in claim 8, wherein said mounting means comprises vertical slots in the walls of said cradle, ribs extending along said slots having spaced holes therein, and retainer pins insertable through aligned holes in said ribs and in said stops.

10. The dumper defined in claim 1, including idler pinions carried by said cradle on opposite sides of said first-mentioned pinion, said first-mentioned pinion engaging one side of said rack and said idler pinions engaging the opposite side thereof. 

1. A dumper comprising a supporting frame, a cradle, pivot means mounting said cradle on said frame for swinging movement from a loading position to an unloading position, and means for swinging said cradle from said loading position to said unloading position comprising a rack extending in an arc centered on the axis of swinging movement of said cradle, a pinion carried by said cradle in engagement with said rack, and power means on said cradle for rotating said pinion.
 2. The dumper defined in claim 1, wherein said rack is a link chain, and said pinion is a sprockEt.
 3. The dumper defined in claim 2, including idler sprockets carried by said cradle on opposite sides of said first-mentioned sprocket, said first-mentioned sprocket engaging one side of said chain and said idler sprockets engaging the opposite side thereof.
 4. The dumper defined in claim 2, wherein said chain is flexible and inextensible, and including an arcuate guide for holding said chain in an arc as aforesaid.
 5. The dumper defined in claim 1, wherein said cradle is adapted to hold a parts container such as a skid box, hold-down means for holding the container down in said cradle comprising a stop engageable with the container, and means for adjustably mounting said stop on said cradle to hold down containers of various sizes.
 6. The dumper defined in claim 2, including idler sprockets carried by said cradle on opposite sides of said first-mentioned sprocket, said first-mentioned sprocket engaging one side of said chain and said idler sprockets engaging the opposite side thereof, said chain being flexible and inextensible, and an arcuate channel-shaped guide for holding said chain in said arc as aforesaid.
 7. The dumper defined in claim 6, including limit switches engageable by said cradle to stop or reverse said motor when said cradle reaches loading and unloading positions respectively.
 8. The dumper defined in claim 7, wherein said cradle is adapted to hold a parts container such as a skid box, hold-down means for holding the container down in said cradle comprising stops engageable with the rim of the container, and means for mounting said stops on said container in adjusted position.
 9. The dumper defined in claim 8, wherein said mounting means comprises vertical slots in the walls of said cradle, ribs extending along said slots having spaced holes therein, and retainer pins insertable through aligned holes in said ribs and in said stops.
 10. The dumper defined in claim 1, including idler pinions carried by said cradle on opposite sides of said first-mentioned pinion, said first-mentioned pinion engaging one side of said rack and said idler pinions engaging the opposite side thereof. 